How Light Can Improve Life for People with Alzheimer’s Disease and Related Dementias

News about Alzheimer’s disease and other dementias is rarely uplifting, but a 2014 study shows that something as simple as exposure to light during the day may improve life for people with the condition. Alzheimer’s and other dementias affect millions of people, causing mild to severe memory loss, which makes it difficult to carry out daily activities such as remember simple things or have a conversation.As many as 5 million Americans over the age of 65 are living with dementia. Unless significant advances are made, this number is expected to almost triple by 2050.[1]

Currently, there is no known cure.  The Center for Diseases Control (CDC) suggest that caregivers try to manage patients’ symptoms, prevent triggers that upset the person, and arrange the environment to ensure his or her safety.  Although it is possible to slow the worsening of some of the symptoms, nothing can completely stop the disease’s process.[2] One important way to improve the quality of life for those with dementia is to modify their environment so that they are less likely to become agitated.

Agitation, which means the person is restless or worried, can cause pacing, sleeplessness, or aggression, and it is one of the major complaints by caregivers of dementia patients.[3] People with dementia often sleep for large parts of the day and are awake for about 40% of the night. Being awake at night increases the likelihood that they will get out of bed and fall in the dark. Perhaps because of this, people with dementia are three times more likely to fall than other older adults.[4] Sleep problems also lead to increased agitation and more problems with memory, as shown by worse scores on tests of recognition and recall.[5]  Moreover, nighttime waking and poor sleep are a leading cause for patients to enter long-term care facilities.

There’s some research to suggest that the sleep problems that people with dementia have may predate and even contribute to the development of the disease. At least one study found that poor sleep was linked to the presence of a molecule that leads to the formation of plaque in the brain—the same kind of plaque found in people with Alzheimer’s disease.[6] If people with Alzheimer’s can sleep better, they may be able to feel and function better and perhaps even slow the progression of their disease. And while there’s no research yet to support this: It’s possible that improving sleep in people who haven’t yet shown any signs of developing Alzheimer’s might prevent the disease or delay its onset.

Can Installing Lights Improve Sleep Quality and Help Alzheimer’s Patients?

alz light bedThe September 2014 study,[7] funded by the National Institute on Aging, included 14 participants who had an average age of 87. They all lived in long-term care facilities in Albany, NY, had mild to moderate dementia, and suffered from sleep and agitation problems. Fluorescent lamps with low level blueish-white light were installed in each participant’s room. A timer turned them on between 6 and 8am, and off at 6pm. If the timer didn’t detect movement in the room for 20 minutes, it turned the lights off. These lights were designed to imitate daylight, telling the body when to be awake.

Researchers collected information about the participants at three points: before these new lights were installed, after 4 weeks with the new lights, and 4 weeks after the lights were removed. Participants wore small devices on their wrists, called Daysimeters, for 7 days at each of these three points to continually record light and participants’ activity levels. The primary caregivers filled out questionnaires about the sleep quality and daily living activities of the participants as well as noting their levels of, depression and agitation.


Just by regulating participants’ exposure to this special light that simulates daylight, researchers found a significant increase in sleep quality (the average sleep time increased by 30 minutes per night). Caregivers reported a significant decrease in depression and agitation in the participants after the lights were installed. Daysimeters showed that participants were more active during light hours and more at rest during dark hours. The increase in daytime activity was especially apparent after lunch. Four weeks after the lights were removed from the rooms, participants’ agitation and depression rose to be closer to that experienced before light installation. Sleep quality decreased after the lights were removed, but not significantly.

Though these are promising results, it’s important to remember that this study was small and only 4 weeks long. There was no comparison group of Alzheimer’s patients who didn’t have the new lights in their room, so we can’t be absolutely sure that these positive changes were a result of the new lights. Also, the caregivers filling out the questionnaire could see that lights had been installed (they didn’t know the goal of the study), so this could have affected the way they scored their patients’ sleep and agitation.

Other weaknesses in the study: Only 10 of the 14 participants used the Daysimeter, and data for the full 7 days was only usable from 6 of those subjects. Wearing the Daysimeter on the wrist presented problems since it was often covered by clothes or a blanket, making data collection difficult. Due to this difficulty, researchers could not evaluate the information from the Daysimeters at the point 4 weeks after the lights were removed. Lastly, the questionnaires were not completed at all three stages for all 14 participants.

The Bottom Line

Researchers only tested the effect of the lighting for 4 weeks. Based on the results, they recommended that future studies look at using the lights for 6 months. Installation of these new lights would be low cost (a light costs about $24 and light timers are around $15). If a more expensive “wall washer” (about $200) is installed with the light, the light is directed toward the ceiling, giving the room an even, diffuse illumination which  uses less energy and minimizes glare. So far, the effect of light on people with Alzheimer’s disease has only been studied in long-term care facilities. If caregivers want to try this at home, they should install the lights in the room where the person with Alzheimer’s spends most of his or her day. If the person is very mobile and moving from room to room or spending regular time outdoors, installing these lights might not provide any additional benefit. Figuring out how to apply these findings to private homes will require more study. Regardless, using a short-wave white light such as this one during the day may be a low cost, no harm way to help Alzheimer’s and related dementias patients get more sleep. This could decrease their agitation and depression, improve their quality of life and lessen the burden on caregivers. Based on this research, caregivers might consider using these lights for any older person with limited mobility and difficulty sleeping.

All articles are reviewed and approved by Dr. Diana Zuckerman and other senior staff.

  1. Alzheimer’s Association. 2013 Alzheimer’s disease facts and figures. Alzheimers Dement. 2013; March 9(2): 208-45.
  2. Centers for Disease Control and Prevention. Alzheimer’s Disease. href=””> July 25, 2014.
  3. Alzheimer’s Caregiving Tips: Coping with Agitation and Aggression. National Institute on Aging. July 2012.
  4. Hanford N, Figueiro M. Light Therapy and Alzheimer’s Disease and Related Dementia: Past, Present, and Future. J Alzheimers Dis. Jan 2013; 33(4): 913-922.
  5. Shin HY, Han HJ, Shin DJ, Park HM, Lee YB, Park KH. Sleep problems associated with behavioral and psychological symptoms as well as cognitive functions in Alzheimer’s disease. J Clin Neurol. 2014 July; 10(3): 203-9.
  6. Yo-El S. Ju, Jennifer S. McLeland, Cristina D. Toedebusch, Chengjie Xiong, Anne M. Fagan, Stephen P. Duntley, John C. Morris, David M. Holtzman. Sleep Quality and Preclinical Alzheimer Disease. Jama Neurol. 2013; May 70(5): 587-593.
  7. Figueiro MG, Plitnick BA, Lok A, Jones GE, Higgins P, Hornick TR, Rea MS. Tailored lighting intervention improves measures of sleep, depression, and agitation in persons with Alzheimer’s disease and related dementia living in long-term care facilities. Clin Interv Aging. 2014; 9: 1527–1537.